The present invention relates in general to sealing and more particularly concerns novel apparatus and techniques for economically effecting a good shaft seal with relatively little apparatus that is compact, lightweight and easily installed.
Shaft seals incorporating permanent magnets, pole pieces and magnetic liquids capture the magnetic liquid between the pole pieces and other parts having relative motion to achieve complete sealing. The prior art includes British Patent Specification No. 783,881; U.S. Pat. Nos. 3,620,584; 3,612,549 and 3,848,879.
These prior art teachings have successfully been used to seal against vacuum and sometimes pressures of several hundred pounds per square inch. Intricate multi-stage seals are commercially available.
It is an important object of the invention to provide an improved shaft seal using magnetic liquid.
It is another object of the invention to achieve the preceding object with relatively little structure that is relatively easy and inexpensive to install.
It is a further object of the invention to achieve one or more of the preceding objects with apparatus that will retain the seal for relatively long periods of time.